In the fields of display and circuit material, demands are recently very high for techniques for highly accurate pattern formation with inorganic materials.
As increasingly small, fine-definition products have been developed in the field of display, demands are very high for advanced techniques for accurate pattern formation. For the production of a barrier rib that divides the pixels on the plasma display panel, for example, it has been hoped to develop a material that serves for pattern formation with an inorganic material, such as glass, with a high level of accuracy and a high aspect ratio.
In the field of circuit material, on the other hand, useful techniques have been needed for accurate processing of ceramic substrates on which IC's are to be mounted. Screen printing and punching are currently used for the pattern formation, but more advanced techniques are needed for highly accurate pattern formation as smaller circuit devices are developed.
Conventionally, pattern formation with inorganic material has been frequently performed by screen printing using a paste consisting of inorganic particles and an organic binder, followed by firing. Screen printing, however, is disadvantageous in forming accurate patterns. Another disadvantage is that the formation of a pattern with a high aspect ratio requires many processing steps since multiple-layer printing is necessary.
To solve this problem, U.S. Pat. No. 4,885,963, U.S. Pat. No. 5,209,688, and JP-A-05-342992 have proposed to perform photolithography using a photosensitive paste. Since the photosensitive paste is low in sensitivity and resolution, however, it is impossible to produce a high-definition barrier rib with a high aspect ratio, and therefore, a long process consisting of several steps (coating, exposure, development, etc.) is required to form a pattern on a barrier rib up to a large thickness of, for example, 80 .mu.m or more.
U.S. Pat. No. 5,209,688 has also proposed a method in which transfer paper is coated with a photosensitive paste, followed by transferring transfer film onto a glass substrate, and JP-A-03-57138 has proposed a method in which grooves on a photoresist layer are filled with a dielectric paste to form a barrier rib. Also, U.S. Pat. No. 5,116,271 has proposed the use of photosensitive organic film to form a barrier rib. These methods, however, have disadvantages arising from the use of transfer film, photoresist, or organic film which require additional manufacturing processes. It should also be noted that a high-definition barrier rib with a high aspect ratio has not been obtained with these methods.
Furthermore, manufacturing of plasma displays sometimes requires pattern formation of the insulator layer or dielectric layer in addition to the barrier rib, and results in problems similar to those with the barrier rib processing.